Our overall objective is to understand the mechanism of active transport in molecular terms. We shall continue to study shock- releasable binding proteins of E. coli and how they are coupled to other proteins in the energy step of active transport. Carrier proteins will be purified from membrane vesicles. We have purified three membrane-bound dehydrogenases and we plan to investigate their localization and mechanism of action in membranes. We shall isolate more mutants, both those involving binding proteins and others where energy coupling is involved. We shall undertake to reassociate carrier proteins and dehydrogenases with membrane vesicles and other systems.